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Journal of Geological Research
Volume 2012 (2012), Article ID 938927, 15 pages
http://dx.doi.org/10.1155/2012/938927
Research Article

Pan-African Paleostresses and Reactivation of the Eburnean Basement Complex in Southeast Ghana (West Africa)

1Département de Géologie, Faculté des Sciences, Université de Lomé, BP 1515, Lomé, Togo
2Aix-Marseille Université, CNRS, IRD, CEREGE UMR34, 13545 Aix en Provence Cedex 04, France
3Geological Survey Department, Koforidua Eastern Region, P.O. Box 672, Koforidua, Ghana

Received 28 March 2012; Revised 18 May 2012; Accepted 25 May 2012

Academic Editor: Quan-Lin Hou

Copyright © 2012 Mahaman Sani Tairou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This faulting tectonics analysis concerns the southernmost segment of the Dahomeyide Orogen and the West-African craton eastern margin in southeast Ghana. The analysis of strike-slip faults in the frontal units of the Dahomeyide Belt indicates that four distinct compressive events (NE-SW, ENE-WSW to E-W, ESE-WNW to SE-NW and SE-NW to SSE-NNW) originated the juxtaposition of the Pan-African Mobile Zone and the West-African craton. These paleostress systems define a clockwise rotation of the compressional axis during the structuring of the Dahomeyide Orogen (650–550 Ma). The SE-NW and SSE-NNW to N-S compressional axes in the cratonic domain and its cover (Volta Basin) suggest that the reactivation of the eastern edge of the West African craton is coeval with the last stages of the Pan-African tectogenesis in southeast Ghana. An extensional episode expressed as late normal faulting is also recorded in this study. This E-W to SE-NW extension, which is particular to the southernmost part of the Dahomeyide Belt, appears to be post-Pan-African. This extension probably contributed to the formation of a major Jurassic rifting zone that originated the Central Atlantic and the Benue Trough.